Endo-Functionalized Cyclic Oligophenylenes: Synthesis and Complexation with a Chiral Phosphoric Acid

Area of Science:

• Organic Chemistry
• Supramolecular Chemistry
• Materials Science

Background:

• Cyclic oligophenylenes are complex molecular architectures with potential applications in host-guest chemistry and materials science.
• Achieving specific functionalization and controlled self-assembly in these macrocycles remains a synthetic challenge.

Purpose of the Study:

• To develop a synthetic route for endo-functionalized cyclic oligophenylenes with perpendicular adjacent benzene rings.
• To investigate the supramolecular structure and host-guest properties of the synthesized macrocycles.

Main Methods:

• Systematic preparation of annulation precursors, including OH- or NH2-functionalized quinquephenyl diboronic acids and septiphenyl dibromo compounds.
• Synthesis of four endo-functionalized cyclic oligophenylenes via Suzuki-Miyaura cross-coupling under dilute conditions.
• Structural characterization using X-ray analysis.

Main Results:

• Successful synthesis of endo-functionalized cyclic oligophenylenes featuring perpendicular benzene rings.
• X-ray analysis revealed a unique 1D channel packing structure formed by the self-assembly of the macrocycles.
• NH2-functionalized macrocycles demonstrated the ability to bind a chiral phosphoric acid within their cavities.

Conclusions:

• The study presents a viable method for constructing complex cyclic oligophenylene architectures.
• The synthesized macrocycles possess unique structural features and promising host-guest capabilities for chiral recognition.